Index: source/cChunkGenerator.cpp
===================================================================
--- source/cChunkGenerator.cpp	(revision 730)
+++ source/cChunkGenerator.cpp	(working copy)
@@ -294,7 +294,7 @@
 
 void cChunkGenerator::InitStructureGens(cIniFile & a_IniFile)
 {
-	AString Structures = a_IniFile.GetValueSet("Generator", "Structures", "Trees,MarbleCaves,OreNests");
+	AString Structures = a_IniFile.GetValueSet("Generator", "Structures", "Trees,MarbleCaves,OreNests,Veins");
 
 	AStringVector Str = StringSplit(Structures, ",");
 	for (AStringVector::const_iterator itr = Str.begin(); itr != Str.end(); ++itr)
@@ -316,6 +316,10 @@
 		{
 			m_StructureGens.push_back(new cStructGenOreNests(m_Seed));
 		}
+		else if (NoCaseCompare(*itr, "veins") == 0)
+		{
+			m_StructureGens.push_back(new cStructGenVeins(m_Seed));
+		}
 		else if (NoCaseCompare(*itr, "ravines") == 0)
 		{
 			m_StructureGens.push_back(new cStructGenRavines(m_Seed, 128));
Index: source/StructGen.cpp
===================================================================
--- source/StructGen.cpp	(revision 730)
+++ source/StructGen.cpp	(working copy)
@@ -7,9 +7,18 @@
 #include "Trees.h"
 
 
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenVeins configuration:
 
+const int MAX_HEIGHT_DIRT = 127;
+const int NUM_NESTS_DIRT = 20;
+const int NEST_SIZE_DIRT = 32;
 
+const int MAX_HEIGHT_GRAVEL = 70;
+const int NUM_NESTS_GRAVEL = 15;
+const int NEST_SIZE_GRAVEL = 32;
 
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // cStructGenOreNests configuration:
 
@@ -401,5 +410,102 @@
 
 
 
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenVeins:
 
+void cStructGenVeins::GenStructures(
+	int a_ChunkX, int a_ChunkZ,
+	cChunkDef::BlockTypes & a_BlockTypes,   // Block types to read and change
+	cChunkDef::BlockNibbles & a_BlockMeta,  // Block meta to read and change
+	cChunkDef::HeightMap & a_HeightMap,     // Height map to read and change by the current data
+	cEntityList & a_Entities,               // Entities may be added or deleted
+	cBlockEntityList & a_BlockEntities      // Block entities may be added or deleted
+)
+{
+	GenerateVein(a_ChunkX, a_ChunkZ, E_BLOCK_DIRT,     MAX_HEIGHT_DIRT,     NUM_NESTS_DIRT,     NEST_SIZE_DIRT,     a_BlockTypes, 10);
+	GenerateVein(a_ChunkX, a_ChunkZ, E_BLOCK_GRAVEL,     MAX_HEIGHT_GRAVEL,     NUM_NESTS_GRAVEL,     NEST_SIZE_GRAVEL,     a_BlockTypes, 11);
+}
 
+
+
+
+void cStructGenVeins::GenerateVein(int a_ChunkX, int a_ChunkZ, BLOCKTYPE a_VeinType, int a_MaxHeight, int a_NumNests, int a_NestSize, cChunkDef::BlockTypes & a_BlockTypes, int a_Seq)
+{
+	// This function generates several "nests" of ore, each nest consisting of number of ore blocks relatively adjacent to each other.
+	// It does so by making a random XYZ walk and adding ore along the way in cuboids of different (random) sizes
+	// Only stone gets replaced with ore, all other blocks stay (so the nest can actually be smaller than specified).
+	
+	for (int i = 0; i < a_NumNests; i++)
+	{
+		int rnd = m_Noise.IntNoise3DInt(a_ChunkX + i, a_Seq, a_ChunkZ + 64 * i) / 8;
+		int BaseX = rnd % cChunkDef::Width;
+		rnd /= cChunkDef::Width;
+		int BaseZ = rnd % cChunkDef::Width;
+		rnd /= cChunkDef::Width;
+		int BaseY = rnd % a_MaxHeight;
+		rnd /= a_MaxHeight;
+		int NestSize = a_NestSize + (rnd % (a_NestSize / 4));  // The actual nest size may be up to 1/4 larger
+		int Num = 0;
+		while (Num < NestSize)
+		{
+			// Put a cuboid around [BaseX, BaseY, BaseZ]
+			int rnd = m_Noise.IntNoise3DInt(a_ChunkX + 64 * i, 2 * a_Seq + Num, a_ChunkZ + 32 * i) / 8;
+			int xsize = rnd % 2;
+			int ysize = (rnd / 4) % 2;
+			int zsize = (rnd / 16) % 2;
+			rnd >>= 8;
+			for (int x = xsize; x >= 0; --x)
+			{
+				int BlockX = BaseX + x;
+				if ((BlockX < 0) || (BlockX >= cChunkDef::Width))
+				{
+					Num++;  // So that the cycle finishes even if the base coords wander away from the chunk
+					continue;
+				}
+				for (int y = ysize; y >= 0; --y)
+				{
+					int BlockY = BaseY + y;
+					if ((BlockY < 0) || (BlockY >= cChunkDef::Height))
+					{
+						Num++;  // So that the cycle finishes even if the base coords wander away from the chunk
+						continue;
+					}
+					for (int z = zsize; z >= 0; --z)
+					{
+						int BlockZ = BaseZ + z;
+						if ((BlockZ < 0) || (BlockZ >= cChunkDef::Width))
+						{
+							Num++;  // So that the cycle finishes even if the base coords wander away from the chunk
+							continue;
+						}
+
+						int Index = cChunkDef::MakeIndexNoCheck(BlockX, BlockY, BlockZ);
+						if (a_BlockTypes[Index] == E_BLOCK_STONE)
+						{
+							a_BlockTypes[Index] = a_VeinType;
+						}
+						Num++;
+					}  // for z
+				}  // for y
+			}  // for x
+			
+			// Move the base to a neighbor voxel
+			switch (rnd % 4)
+			{
+				case 0: BaseX--; break;
+				case 1: BaseX++; break;
+			}
+			switch ((rnd >> 3) % 4)
+			{
+				case 0: BaseY--; break;
+				case 1: BaseY++; break;
+			}
+			switch ((rnd >> 6) % 4)
+			{
+				case 0: BaseZ--; break;
+				case 1: BaseZ++; break;
+			}
+		}  // while (Num < NumBlocks)
+	}  // for i - NumNests
+}
+
Index: source/StructGen.h
===================================================================
--- source/StructGen.h	(revision 730)
+++ source/StructGen.h	(working copy)
@@ -5,6 +5,7 @@
 	- cStructGenTrees
 	- cStructGenMarbleCaves
 	- cStructGenOres
+	- cStructGenVeins
 */
 
 
@@ -110,3 +111,29 @@
 
 
 
+class cStructGenVeins :
+	public cStructureGen
+{
+public:
+	cStructGenVeins(int a_Seed) : m_Noise(a_Seed), m_Seed(a_Seed) {}
+	
+protected:
+	cNoise m_Noise;
+	int    m_Seed;
+	
+	// cStructureGen override:
+	virtual void GenStructures(
+		int a_ChunkX, int a_ChunkZ,
+		cChunkDef::BlockTypes & a_BlockTypes,   // Block types to read and change
+		cChunkDef::BlockNibbles & a_BlockMeta,  // Block meta to read and change
+		cChunkDef::HeightMap & a_HeightMap,     // Height map to read and change by the current data
+		cEntityList & a_Entities,               // Entities may be added or deleted
+		cBlockEntityList & a_BlockEntities      // Block entities may be added or deleted
+	) override;
+	
+	void GenerateVein(int a_ChunkX, int a_ChunkZ, BLOCKTYPE a_OreType, int a_MaxHeight, int a_NumNests, int a_NestSize, cChunkDef::BlockTypes & a_BlockTypes, int a_Seq);
+} ;
+
+
+
+